1. Field of the Invention
The invention relates to a high-lift system for an aircraft and a method of using the system in an aircraft.
2. Discussion of Background Information
Large numbers of high-lift systems for aircraft are known. In general, these comprise high-lift flaps which are arranged on the aircraft mainplane and can be moved by means of an actuating drive between a retracted position, in which the flap continuously complements the wing profile essentially without any gap, and a plurality of extended positions, in which a slot of given width is formed between the wing and the flap and the flap is positioned at a predetermined angle with respect to the wing profile. The flap is extended in an entirely general manner in a movement which on the one hand comprises movement of the flap with respect to the wing to the rear, and thus lengthening of the effective wing profile, and on the other hand an increase in the incidence angle of the flap with the profile curvature being increased, thus resulting in an increase in the aerodynamic lift. Air flows at high speed through the slot that is formed between the flap and the wing when in the extended position, from the lower face of the wing to the upper face of the flap, thus making a further contribution to the increase in lift.
On the one hand, so-called Fowler flaps should be mentioned and are in particular among the most widely used types of high-lift systems nowadays. In the case of Fowler flaps, while the flap is being extended, it moves backwards away from the wing forming the slot between the wing and the flap, with an increase in the incidence angle of the flap being superimposed on this movement, particularly as the flap extension increases. This combined movement is also referred to as a Fowler movement.
On the other hand, an arrangement which is referred to as dropped hinge kinematics or pivoting flap kinematics is known, in which the high-lift flap is mounted on a flap lever such that it can pivot about a rotation point that is provided under the wing. As the name itself implies, the flap is moved about the rotation point, which is located under the wing, during extension, on a path which is in the form of a circular arc.